Early activation of the hypothalamic-pituitary-adrenal-axis in very-low-birth-weight infants with small thymus at birth.

BACKGROUND: An acute thymic involution in human fetuses and newborns has been described in very-low-birth-weight (VLBW) infants with histological chorioamnionitis. However, the mechanisms of thymic involution remain to be clarified. Here, we tested the hypothesis that an activation of the hypothalamic-pituitary-adrenal (HPA) axis occurs in VLBW infants with acute thymic involution at birth. METHODS: A total of 180 randomly selected VLBW newborns (28.8 +/- 3.15 wk gestation; 1093 +/- 305 g) entered the study. Thymic size was measured on standard chest radiographs at birth, and expressed as the ratio between the transverse diameter of the cardiothymic image at the level of the carina (CT) and that of the thorax (T). CT/T < 0.28 was considered to indicate a small thymic size. Plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations were determined on days 1 (d-1) and 7 (d-7), and at 1 month (mo-1). Results. A total of 66 (36.7%) newborns had CT/T < 0.28. Infants with small thymus had significantly increased cortisol on d-1 ( approximately 5.2-folds) [median: 18.95 (95% CI: 11.20-39.4) microg/dl vs. 3.66 (1.94-6.82) microg/dl, p < 0.0001)] and d-7( approximately 1.7-folds) [12.0 (4.39-22.97) microg/dl vs. 7.8 (3.63-12.8) microg/dl, p = 0.0384)], as compared with those with normal thymic size, together with higher adrenocorticotropic hormone (ACTH) concentrations on d-1 ( approximately 1.9-folds) [28 (15.6-61.07) pg/ml vs. 14.9 (9.0-23.42) pg/ml, p = 0.0005)], while no significant differences for cortisol at mo-1 or ACTH concentrations on d-7 and mo-1 were evidenced (p > 0.50). From a multivariate logistic regression analysis, a small thymus at birth was a significant independent predictor of plasma cortisol concentrations in the top-quartile (OR = 14.4; 95% CI: 6.079-34.11), and plasma ACTH concentrations in the top-quartile (OR = 4.40 (95% CI: 1.99-9.74) on d-1 (results adjusted for variables significant at univariate analysis). CONCLUSIONS: Our data indicated the presence of a previously unrecognized, early activation of the HPA axis in VLBW newborns with a small thymus at birth.

Epstein-Barr virus and gastric cancer: data and unanswered questions.

Sixty-five unselected cases of gastric cancer have been analysed for EBV DNA by polymerase chain reaction, in situ hybridization and immunohistochemistry for CD21 antigen expression. Four cases were found EBV-positive by PCR, while ISH yielded positive results in 3 of these cases, demonstrating EBV in the nuclei of cancerous cells. CD21 antigen was expressed in cancerous cells in all 3 ISH-positive cases. All the EBV-positive cancers of the present series were poorly to moderately differentiated adenocarcinomas with prominent lymphoid infiltration. These results are discussed also on the basis of the literature.

Plasma levels of luteinizing hormone, estradiol and androstenedione in sows with inadequate plasma progesterone.

The authors report the profiles of luteinizing hormone (LH), estradiol (E2), progesterone (P) and androstenedione (A) in some female pigs with altered plasma hormonal levels. Twenty cycles are described and 19 out of them are characterized by low plasma P in luteal phase of different etiology, at least as measured by hormone concentrations. The following disorders are observed: a) possible impairment of follicular maturation; b) impaired LH secretion in presence of too high E2; c) low LH base-line values; d) inadequate luteal phase; e) short luteal phase; f) heat disorders. An attempt is made to correlate the altered hormonal profiles with the high rate of summer conception failure in sows.

Endocrine profiles of sows during the oestrous cycle.

We measured the plasma concentrations of luteinizing hormone (LH), oestradiol (E2), progesterone (P), 17 alpha-hydroxy progesterone (17P), androstenediona (A) and testosterone (T) at oestrus and during the oestrous cycle for four consecutive cycles in a group of 15 normal sows. The results show that at oestrus the peak LH value was preceded, 24 hours earlier, by an E2 peak, and indicate that the LH rise begins when E2 concentrations reach their highest value. During diestrus, concentrations of LH and E2 were constantly low, P and 17P were characterized by lowest concentrations during the oestrous period which showed significant (p less than 0.001), progressive increases from the second day after the LH ovulatory peak, to reach their highest values after 8-14 days. The 17P decrease in proestrus precedes that of P.T and A concentrations showed a significant (p less than 0.001) increase 2 days before the LH ovulatory peak; high plasma concentrations of both androgens were maintained until the LH peak occurred. Measurements taken in consecutive cycles in the same animals showed a high reproducibility of the hormone concentrations examined, which showed similar patterns and values in each of the cycles studied. This high reproducibility suggests that these hormones have an important physiological role and may affect oestrous behaviour.